1. The Field of the Invention
The present invention relates to wireless networks, and more specifically, to using directional antennas to increase signal strength and enhance throughput in wireless networks.
2. Background and Relevant Art
Computer systems and related technology affect many aspects of society. Indeed, the computer system's ability to process information has transformed the way we live and work. Computer systems now commonly perform a host of tasks (e.g., word processing, scheduling, and database management) that prior to the advent of the computer system were performed manually. More recently, computer systems have been coupled to one another to form both wired and wireless computer networks over which the computer systems can communicate electronically to share data. As a result, many tasks performed at a computer system (e.g., voice communication, accessing electronic mail, electronic conferencing, web browsing) include electronic communication with one or more other computer systems via wired and/or wireless computer networks.
For example, a number of computer systems can be coupled to a data hub through corresponding wired connections (e.g., category 5 cable) to form a wired network (e.g., an Ethernet segment). Similarly, a number of wireless computer systems (commonly referred to as “stations”) can be coupled to a wireless access point (“AP”) through corresponding wireless connections (e.g., resulting from appropriate communication between radio transmitters and receivers) to form a wireless network (e.g., an IEEE 802.11 network). Further, a data hub and/or an AP can be connected to other data hubs, APs, or other network devices, such as routers, gateways, and switches to form more complex networks (including both wired and wireless connections).
When computer systems communicate electronically, electronic data will often pass through a protocol stack that performs operations on the electronic data (e.g., packetizing, routing, flow control). The Open System Interconnect (“OSI”) model is an example of a networking framework for implementing a protocol stack. The OSI model breaks down the operations for transferring electronic data into seven distinct “layers,” each designated to perform certain operations in the data transfer process. While protocol stacks can potentially implement each of the layers, many protocol stacks implement only selective layers for use in transferring electronic data across a network.
When data is received from a network it enters the physical layer and is passed up to higher intermediate layers and then eventually received at an application layer. The physical layer, the lower most layer, is responsible for converting electrical impulses, light, or radio waves into a bit stream and vice versa. On the other hand, when data is transmitted from a computer system, it originates at the application layer and is passed down to intermediate lower layers and then onto a network. The application layer, the upper most layer, is responsible for supporting applications and end-user processes, such as, for example, electronic conferencing software, electronic mail clients, web browsers, etc.
An intermediate layer incorporated by most protocol stacks is the Data Link layer. The Data Link layer decodes data packets (received from higher layers) into bit streams for use by the physical layer and encodes bit steams (received from the physical layer) into data packets for use by higher layers. A sub-layer typically included in the Data Link layer is the Media Access Control (“MAC”) layer, which implements protocols for moving data packets onto a shared channel (e.g., an Ethernet segment or an 802.11 channel).
However, to access a medium a computer system must be able to sense the medium. In a wireless environment, sensing a wireless medium (e.g., an 802.11 channel) can be difficult, and at times impossible, depending on how a station and an access point are physically separated. Access points typically include an omni-directional antenna. Accordingly, when no physical bariers exist (e.g., walls, floors, buildings, etc.), the range of the omni-directional antenna essentially results in a spherical region around the access point. When a station is within a particular range of the access point, the omni-directional antenna enables the access point to meaningfully send data to and receive data from the station. That is, within the particular range, transmitted radio signals have sufficient signal strength such that a physical layer can convert the radio signals into a bit stream.
However, when a station is at or near the range of an omni-directional antenna and/or is separated from an omni-directional antenna by physical bariers, radio signal propagation loss (e.g., in the 2.4 GHz band or 5 GHz band) can significantly reduce the speed and reliability of data transferred between a station and an access point. When the station is outside the range of the access point or when substantial physical bariers exist, meaningful communication between a station and an access point may not be possible. For example, due to propagation loss, an data rate can be significantly reduced essentially making communication with the omni-directional antenna impossible. Further, while am omni-directional antenna may have sufficient signal strength to detect that radio waves are being transmitted (e.g., from a station to an access point or vice versa), the signal strength may be degraded such that it is difficult, or even impossible, to determine what data is being represented by the radio waves. That is, a physical layer may not be able to generate a bit stream from the degraded radio waves. Therefore systems, methods, and computer program products for reducing the effects of propagation loss would be advantageous.